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.Dd Feb 23, 2015
.Dt TIMERFD 7
.Os
.Sh NAME
.Nm timerfd
.Nd Linux-compatible timer notification facility
.Sh SYNOPSIS
.In sys/timerfd.h
.Sh DESCRIPTION
.Nm
is a Linux-borne facility for creating POSIX timers and
receiving their subsequent events via a file descriptor.
The facility itself is arguably unnecessary:
portable code can either use the timeout value present in
.Xr poll 2 /
.Xr port_get 3C
or -- if this is deemed of unacceptably poor resolution -- create a POSIX timer
via
.Xr timer_create 3C
and use the resulting signal to induce an
.Sy EINTR
to polling threads.  (For code that need not be
portable, the
.Sy SIGEV_PORT
signal notification allows for explicit, event-oriented timer notification to be
sent to a specified port; see
.Xr signal.h 3HEAD
for details.) This facility therefore exists only to accommodate Linux-borne
applications and binaries; it is compatible with its Linux antecedent in both
binary interface and in semantics.
.Sh SEE ALSO
.Xr timerfd_create 3C ,
.Xr timerfd_gettime 3C ,
.Xr timerfd_settime 3C
